Apparatus for automated maintenance of aircraft structural elements

1. An automated apparatus for moving an end effector over a surface of an airfoil-shaped body, comprising:

a chassis configured to be mounted on an airfoil-shaped body, said chassis comprising forward and rearward assemblies which are linearly displaceable relative to each other along a first axis, said rearward assembly comprising an upper rearward body part and an axle having a second axis perpendicular to said first axis and fixed relative to the upper rearward body part;

a drive roller rotatably mounted to said chassis;

a first drive motor mounted to said chassis and arranged to drive rotation of said drive roller;

a cross beam rotatably mounted to said axle of said rearward assembly of said chassis and not driven to rotate by a motor;

first and second rollers rotatably mounted to opposing ends of said cross beam for rotation about third and fourth axes respectively, said third and fourth axes being parallel to said second axis; and

a second drive motor for driving rotation of said first roller about said third axis,

wherein said rearward assembly further comprises a lower rearward body part and a support member having one end attached to said lower rearward body part and another end attached to one end of said axle, the apparatus further comprising a first ball and socket bearing supported by said lower rearward body part and a second ball and socket bearing supported by said upper rearward body part.

2. The apparatus as recited in claim 1 , further comprising:

a drive pulley affixed to an output shaft of said second drive motor;

a first follower pulley rotatably coupled to said cross beam and fixedly coupled to said first roller; and

a first drive belt or chain that couples the first follower pulley to the drive pulley.

3. The apparatus as recited in claim 2 , further comprising:

a second follower pulley rotatably coupled to said cross beam and fixedly coupled to said second roller; and

a second drive belt or chain that couples the second follower pulley to the drive pulley.

4. The apparatus as recited in claim 1 , wherein said second axis is at a midpoint between the third and fourth axes.

5. An automated apparatus for moving an end effector over a surface of an airfoil-shaped body, comprising:

a chassis configured to be mounted on an airfoil-shaped body, said chassis comprising forward and rearward assemblies which are linearly displaceable relative to each other along a first axis, said rearward assembly comprising an upper rearward body part and an axle having a second axis perpendicular to said first axis and fixed relative to the upper rearward body part;

a drive roller rotatably mounted to said chassis;

a first drive motor mounted to said chassis and arranged to drive rotation of said drive roller;

a cross beam rotatably mounted to said axle of said rearward assembly of said chassis for rotation about the second axis perpendicular to said first axis; and

first and second rollers rotatably mounted to opposing ends of said cross beam for rotation about third and fourth axes respectively, said third and fourth axes being parallel to said second axis,

wherein said rearward assembly further comprises a lower rearward body part and a support member having one end attached to said lower rearward body part and another end attached to one end of said axle, the apparatus further comprising a first ball and socket bearing supported by said lower rearward body part and a second ball and socket bearing supported by said upper rearward body part.

6. The apparatus as recited in claim 5 , further comprising a second drive motor arranged to drive rotation of said cross beam about said second axis.

7. The apparatus as recited in claim 6 , further comprising a third drive motor arranged to drive rotation of said first roller relative to said cross beam.

8. The apparatus as recited in claim 6 , wherein said rearward assembly comprises a support member, said second drive motor is mounted to said support member and comprises an output shaft, and said cross beam is mounted to said output shaft of said second drive motor.

9. The apparatus as recited in claim 6 , further comprising a pivot gear mounted to an output shaft of said second drive motor and an axle reaction gear affixed to said axle, each of said pivot gear and said axle reaction gear comprising teeth that are interengaged.

10. The apparatus as recited in claim 9 , wherein said second drive motor is housed inside said cross beam and said pivot gear is disposed outside said cross beam.

11. The apparatus as recited in claim 9 , further comprising a third drive motor arranged to drive rotation of said first roller relative to said cross beam and a fourth drive motor arranged to drive rotation of said second roller relative to said cross beam.

12. The apparatus as recited in claim 11 , wherein said second, third and fourth drive motors are housed inside said cross beam and said pivot gear is disposed outside said cross beam.

13. The apparatus as recited in claim 6 , further comprising a linear actuator for linearly displacing said rearward assembly relative to said forward assembly of said chassis, said linear actuator comprising a third drive motor.

14. The apparatus as recited in claim 13 , further comprising a computer system configured to control said second and third drive motors in a protrusion climbing mode such that said cross beam rotates about said second axis and linearly displaces along said first axis concurrently.

15. The apparatus as recited in claim 14 , wherein said computer system is further configured to control said first drive motor in a chassis displacement mode such that said drive roller rotates while said cross beam does not rotate.

16. The apparatus as recited in claim 5 , further comprising a second drive motor arranged to drive rotation of said first roller relative to said cross beam.

17. The apparatus as recited in claim 5 , wherein said second axis is at a midpoint between the third and fourth axes.